The present invention relates to a free line switch arrangement for power-and-free trolley conveyors wherein the free line comprises two rails.
Conventional power-and-free trolley conveyors comprise a free line rail extending immediately below a power line rail and carriers suspended from the free line rail and each thereby supported at its center portion. Accordingly the power line rail, free line rail and other parts are positioned immediately above the article placed on the carrier, with the resulting likelihood that oil, dust, etc. will fall onto the article. To render the article on the carrier free from deposits such as oil and dust, we have already proposed a power-and-free trolley conveyor comprising a power line rail, a free line rail disposed immediately below the power line rail, another free line rail provided at one side of the free line rail in parallel thereto, and carriers suspended from the free line rails and each thereby supported at its opposite sides (Application for Japanese Utility Model Registration No. 172007/80). However, at a branch or confluent junction of free lines of such a trolley conveyor, the two rails of a first free line are joined to the two rails of a second free line, with one of the rails of one free line intersecting one of the rails of the other free line, so that the switch arrangement needed for diverting carriers at the branch or confluent junction generally becomes complex in construction.